Technical Abstract:
The Snowmelt Runoff Model(SRM) has been developed and tested in small to large basins worldwide. SRM has been found to be very useful for understanding snowmelt processes as well as for simulating or forecasting snowmelt-derived water supplies. SRM is being used in New Mexico in a NSF-funded EPSCoR(Experimental Program to Stimulate Competitive Research) project. All important snowmelt sub basins of the Rio Grande in New Mexico and Colorado are being studied to provide required snow covered area inputs to SRM in and attempt to answer what the climate change impacts on New Mexico’s mountain sources of water are. Landsat and MODIS satellites are being employed to remotely sense snow cover in both New Mexico and Colorado. Initial mapping provided information that indicated that resolution better than provided by MODIS(250-500m) would be necessary, so we have used Landsat(15-30m) when available. Additionally, it seemed that the satellite mapping was not detecting all the snow cover in the forest snow zone. The forest cover was delineated with high resolution, but much less frequent aerial photography. The addition of these approaches provides better hydrologic simulations without resorting to changes in the SRM parameters. SRM has a further advantage for evaluating climate change effects on water supply because it has an algorithm that automatically takes any future climate scenario into account. Such future climates are being derived from climate models run over the Rio Grande basin. Various snowmelt algorithms in SRM are being used independently in Idaho basins driven by another important snow variable: the daily snow water equivalent available from NRCS SNOTEL sites. It is important to compare the output of basins in the northern Rockies(Idaho) to those in the southern Rockies(New Mexico/Colorado). Typically, a La Nina year like 2011 in Idaho produces above average snow accumulation and runoff whereas in New Mexico or Colorado, La Nina produces well below average snowpacks and runoff. SRM snowmelt calculations can be made using either snow covered area or snow water equivalent inputs. This presentation will show examples of each of these SRM-related products.